Modulation of DNA synthesis in aortic smooth muscle cells by dinitrotoluenes

Studies were conducted to determine if in vivo exposure to dinitrotoluenes (DNT), which is associated with circulatory disorders of atherosclerotic etiology in humans, is associated with alterations of vascular smooth muscle cells (SMC) consistent with the atherogenic process. Sprague-Dawley rats (150-180 g) were injected IP for 5 days/week for 8 weeks with 2,4- or 2,6-DNT (0.5, 5, or 10 mg/kg) or medium chain triglyceride (MCT) oil. Histopathologic evaluation of aortae from animals exposed to either isomer showed dysplasia and rearrangement of SMC at all doses tested. Reduced ³H-thymidine incorporation was observed in primary cultures of aortic SMC from DNT-exposed animals relative to vehicle controls. This inhibitory response was maintained for up to two passages in culture after which a significant increase in thymidine incorporation was observed. Exposure of SMC from naive animals to DNT in vitro (1–100 µM) did not alter the extent of thymidine incorporation in cycling or growth-arrested cultures. In contrast, exposure to 2,4- or 2,6-diaminotoluene (DAT) (1–100 µM), carcinogens which share toxic metabolic intermediates in common with DNT, inhibited replicative DNA synthesis and stimulated unscheduled DNA synthesis in cycling and growth-arrested cultures of SMC, respectively. Our results suggest that modulation of DNA synthesis in aortic SMC by DNT metabolites generated in vivo contribute to the development of vascular lesions.Abbreviation DAT diaminotuluene - tDNT technical grade dinitrotoluene - DNT dinitrotoluenes - HU hydroxyurea - IP intraperitoneal - LDH lactate dehydrogenase - MCT oil medium chain triglyceride - NPTC non-protein thiol content - RDS replicative DNA synthesis - SEM standard error of the mean - SMC smooth muscle cells - UDS unscheduled DNA synthesis     

Reduced Global Genetic Differentiation of Exploited Marine Fish Species

Knowledge on genetic structure is key to understand species connectivity patterns and to define the spatiotemporal scales over which conservation management plans should be designed and implemented. The distribution of genetic diversity (within and among populations) greatly influences species ability to cope and adapt to environmental changes, ultimately determining their long-term resilience to ecological disturbances. Yet, the drivers shaping connectivity and structure in marine fish populations remain elusive, as are the effects of fishing activities on genetic subdivision. To investigate these questions, we conducted a meta-analysis and compiled genetic differentiation data (F_ST/Φ_ST estimates) for more than 170 fish species from over 200 published studies globally distributed. We modeled the effects of multiple life-history traits, distance metrics, and methodological factors on observed population differentiation indices and specifically tested whether any signal arising from different exposure to fishing exploitation could be detected. Although the myriad of variables shaping genetic structure makes it challenging to isolate the influence of single drivers, results showed a significant correlation between commercial importance and genetic structure, with widespread lower population differentiation in commercially exploited species. Moreover, models indicate that variables commonly used as proxy for connectivity, such as larval pelagic duration, might be insufficient, and suggest that deep-sea species may disperse further. Overall, these results contribute to the growing body of knowledge on marine genetic connectivity and suggest a potential effect of commercial fisheries on the homogenization of genetic diversity, highlighting the need for additional research focused on dispersal ecology to ensure long-term sustainability of exploited marine species.     

Role of endocannabinoids in brain development.

In addition to those functions that have been extensively addressed in this special issue, such as nociception, motor activity, neuroendocrine regulation, immune function and others, the endogenous cannabinoid system seems to play also a role in neural development. This view is based on a three-fold evidence. A first evidence emerges from neurotoxicological studies that showed that synthetic and plant-derived cannabinoids, when administered to pregnant rats, produced a variety of changes in the maturation of several neurotransmitters and their associated-behaviors in their pups, changes that were evident at different stages of brain development. A second evidence comes from studies that demonstrated the early appearance of elements of the endogenous cannabinoid system (receptors and ligands) during the brain development. The atypical location of these elements during fetal and early postnatal periods favours the notion that this system may play a role in specific molecular events related to neural development. Finally, a third evidence derives from studies using cultures of fetal glial or neuronal cells. Cannabinoid receptors are present in some of these cultured cells and their activation produced a set of cellular effects consistent with a role of this system in the process of neural development. All this likely supports that endocannabinoids, early synthesized in nervous cells, play a role in events related to development, by acting through the activation of second messenger-coupled cannabinoid receptors.     

Glucose and ketone bodies production in hepatocytes isolated from fetuses at term--II. Effect of maternal adrenalectomy

Glucose and ketone bodies production has been studied in hepatocytes isolated from fetuses at term of fed and fasted adrenalectomized mothers. Maternal adrenalectomy diminishes the fetal liver weight. This effect is increased when the adrenalectomized pregnant rat is fasted for the last 2 days of gestation. Maternal adrenalectomy diminishes glucose production in hepatocytes isolated from fetuses at term. This diminution is markedly greater when the adrenalectomized pregnant rat is fasted for the last 48 hr of gestation. Maternal adrenalectomy diminishes ketone bodies production in hepatocytes isolated from fetuses at term.     

Glucose and ketone bodies production in hepatocytes isolated from fetuses at term--I. Effect of maternal fasting

The effect produced by maternal fasting on glucose and ketone bodies production has been studied in hepatocytes isolated from fetal rat. Maternal fasting produces a decrease in the weight of fetal liver. Maternal fasting produces a decrease in glucose production, both from endogenous substrates and adding lactate (10 mM) to the incubation medium. Maternal fasting produces an increase in ketone bodies production, both from endogenous substrates and adding acetate (5 mM) to the incubation medium.     

Allometric growth and adaptive value of exaggerated body parts in the larvae of Gratiana spadicea (Klug) (Coleoptera: Chrysomelidae)

1. Larvae of tortoise beetles present exaggerated body parts in association with an abdominal shield, which is made of faeces and exuviae that are deposited on the urogomphi throughout ontogeny. Growth trajectories and scaling relationships of these functional structures associated with the shield, if any, are unknown. 2. This study of Gratiana spadicea first tested, under field conditions, whether there is adaptive value associated with the shield regarding protection against predation and sunlight. Then, under laboratory conditions, the growth trajectory and allometric relationships among body parts were investigated, including scoli, individual and apparent furcae, and shield. The influence of food deprivation on the development of these structures was also determined. 3. Findings from previous studies were confirmed, suggesting that the adaptive value assigned to the shield is related to protection against predators. The present study demonstrated for the first time that the shield acts as a parasol in cassidines, decreasing the exposure of their larval body to sunlight. The scoli and apparent furca are exaggerated structures of G. spadicea, the development of which involves allometric growth and greater energetic investment (positive allometry) during ontogeny. There was proportionally less energetic investment for somatic construction of individual furca (negative allometry) due to the accumulation of the exuviae. 4. The possible consequences, in terms of developmental costs and survivorship benefits associated with the evolution of such exaggerated structures, are discussed.     

Caring soils for sustainable land uses

The aim of the article is to develop and explore the idea that soil health is an essential element in combating climate change and promoting food security. An important aspect of this is that soil, rather than simply serving to support plants and as a niche for animals and microbes, also functions as a natural reactor that, through a series of chemical and biological reactions, purifies water, replenish aquifers and maintains equilibria in surface waters. This topic is particularly timely given the recent announcement of the Mission program for Health of Soils by the European Commission. Within this realm, the article intends to catalyze and promote the debate around what defines sustainable agriculture in order to help shape its future.     

Identification of novel HLA-B27 ligands derived from polymorphic regions of its own or other class I molecules based on direct generation by 20 S proteasome.

HLA-B27 is strongly associated with ankylosing spondylitis. Natural HLA-B27 ligands derived from polymorphic regions of its own or other class I HLA molecules might be involved in autoimmunity or provide diversity among HLA-B27-bound peptide repertoires from individuals. In particular, an 11-mer spanning HLA-B27 residues 169-179 is a natural HLA-B27 ligand with homology to proteins from Gram-negative bacteria. Proteasomal digestion of synthetic substrates demonstrated direct generation of the B27-(169-179) ligand. Cleavage after residue 181 generated a B27-(169-181) 13-mer that was subsequently found as a natural ligand of B*2705 and B*2704. Its binding to HLA-B27 subtypes in vivo correlated better than B27-(169-179) with association to spondyloarthropathy. Proteasomal cleavage generated also a peptide spanning B*2705 residues 150-158. This region is polymorphic among HLA-B27 subtypes and class I HLA antigens. The peptide was a natural B*2704 ligand. Since this subtype differs from B*2705 at residue 152, it was concluded that the ligand arose from HLA-B*3503, synthesized in the cells used as a source for B*2704-bound peptides. Thus, polymorphic HLA-B27 ligands derived from HLA-B27 or other class I molecules are directly produced by the 20 S proteasome in vitro, and this can be used for identification of such ligands in the constitutive HLA-B27-bound peptide pool.